This project is for the development and evaluation of strategies for control of the artificial heart using a microcomputer based automatic control system. We propose to evaluate the concept of utilizing P-wave signals for the control of the artificial heart as well as to evaluate the relative significance of the use of atrial pressures and aortic pressure as input variables to the control system. This study will be conducted within the framework of optimal control theroy in which the performance of control concepts will be evaluated on the basis of a performance measure which includes cardiac output and the deviation of atrial pressures and aortic pressure from desired levels. The use of optimal and adaptive control techniques will enable us to develop control algorithms which yield maximum pump efficiency while keeping systemic pressures within normal physiological limits. The proposed research has become feasible because of the development of computer technology which provides us with the flexibility to test alternative control strategies by switching to alternative algorithms stored in the computer memory. The applicants are uniquely equipped to conduct this research because of their development of a microcomputer based control system which was built at the University of Houston in collaboration with the Texas Heart Institute and consists of two basic segments: (1) the P-wave controller and (2) the drive pressure controller. The p-wave signal, atrial pressures, and aortic pressure are fed into the control system which regulates the systolic and diastolic time intervals and pneumatic drive pressures. The P-wave controller has already been used in successful in vivo experiments at the Texas Heart Institute. The drive pressure control unit is ready for in vitro testing.